Army Reserve Staff Sgt. Elizabeth Stewart, a medical treatment noncommissioned officer-in-charge and a civilian nurse, assigned to the 456th Medical Company (Area Support), Chemical Response Element-A, keeps a watchful eye on Soldiers performing medical tasks during a mass decontamination training event at the Muscatatuck Urban Training Center in Butlerville, Indiana, during exercise Guardian Response 21. Army Reserve and National Guard Soldiers, Engineers, chemical, biological, radiological and nuclear (CBRN) specialists, as well as medical units are conducting Defense Support of Civil Authorities (DSCA) training at the multi-million dollar facility to help prepare them to respond to a CBRN catastrophe at home or abroad. (Official U.S. Army Reserve photo by Sgt. 1st Class Brent C. Powell)